You are somehow imagining that this will be administered in a strictly controlled manner. It won't. In fact, I will be very sad if it's not part of the regular capitalist marketplace.

Will it lead to overpopulation? Yes. Bloody wars? Yes. Almost completely stagnant population? Suicides left and right by 200-y.o. people? Perverse class imbalance? Complete overhaul of society as we know it? Yesyesyesnotreally.

Because once you institutionalise and put such and such rules in place (a bureaucracy), people stop thinking. They stop thinking and become not people, but things - and they do it to themselves, willingly.

And that is the greatest crime of all.